Evidence of morphotropic phase boundary displacement in lead-free (Bi0.5Na0.5)1 − xBaxTiO3 polycrystalline thin films
Evidence of morphotropic phase boundary displacement in lead-free (Bi0.5Na0.5)1 − xBaxTiO3 polycrystalline thin films
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DOI：
10.1016/j.matlet.2011.05.111
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发表时间：
2011-09
影响因子：
3
通讯作者：
Í. Bretos;David Alonso-San José;R. Jiménez;J. Ricote;M. Calzada
中科院分区：
文献类型：
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作者：
Í. Bretos;David Alonso-San José;R. Jiménez;J. Ricote;M. Calzada
采用化学溶液沉积法在Pt/−/SiO_2/(0.150)Si衬底上制备了x=0.055、0.100和0.150的无铅(Bi0.5Na0.5)1 BNBT薄膜。研究了薄膜的介电行为，并利用观察到的铁电-反铁电相变确定了x~0.100(BNBT-10)组分的准同型相界，该值与报道的块体材料(BNBT-5.5)的相界位置不同。来自薄膜构型的外部效应(例如，微应变、残余应力)可能是导致MPB漂移的原因。结果表明，该化合物的介电常数得到了显著的改善，表现出了到目前为止BNBT系统薄膜的最佳铁电响应(Pr=13.0μC/cm~2，EC=70KV/cm)。
Lead-free (Bi0.5Na0.5)1−xBaxTiO3(BNBT) thin films with compositions at x=0.055, 0.100, and 0.150 were prepared by chemical solution deposition on Pt/TiO2/SiO2/(100)Si substrates. The dielectric behavior of the films was studied, and the ferroelectric-antiferroelectric phase transition observed was used to situate the morphotropic phase boundary (MPB) for compositions with x~0.100 (BNBT-10), a value that differs from that reported for bulk materials (BNBT-5.5). Extrinsic effects derived from the thin-film configuration (e.g., microstrains, residual stresses) may be responsible for the shift of the MPB. Consequently, the dielectric permittivity is significantly improved for this composition, showing the best ferroelectric response obtained up to now for films of the BNBT system (Pr=13.0μC/cm2, Ec=70kV/cm).